Re: substring matching backend names...

[Pavlos Parissis]

On 10/07/2015 10:32 μμ, Phillip Decker wrote:
> Hello again,
>  
> I was migrating a setup from the older style acl-based host to backend 
> mapping, to the newer
> map-based approach, e.g.
>  
> use_backend  %[req.hdr(host),lower,map_beg(mapping.conf,default)]
>  
> and that works fine.  But now I'm tempted to simply name the backends after 
> each servername,
> (eg. 'mail' from mail.google.com , or 'maps' from 
> maps.google.com
> ). 
>  
> Which in my imagination would look something like:
>  
> use_backend %[req.hdr_beg(host),lower]
>  
> But is there a way to substring or regex off the front of the host string, 
> and pass that to the
> use_backend call?
>  
> In other words, continuing the google.com  example, if 
> people are hitting
> the server with "host: mail.google.com ", and 
> maps.google.com
> , and just for completeness, notes.books.google.com
> , I'd like to have backends:
>  
> backend mail
>mode http
>foo
>
>  
> backend maps
>mode http
>bar
>...
>  
>  backend notes.books
>mode http
>baz
>..
>  
> Is there a way to accomplish this without building them into a mapped file in 
> 1.5.x? 
>  
> (1.6 solutions are okay too, but won't be able to move to that until it's in 
> stable.)

1.6 is *stable*. It has been running fine in several setups I manage since 
dev6:-)
But, I guess you meant in *stable* repo of X distribution, right?

Cheers,
Pavlos






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Re: substring matching backend names...

[Phillip Decker]

Tested, and very nice; that works!

Thanks so much!

Phillip

On Sat, Jul 11, 2015 at 2:20 AM, Willy Tarreau w...@1wt.eu wrote:

 Hi,

 On Fri, Jul 10, 2015 at 04:32:38PM -0400, Phillip Decker wrote:
  Hello again,
 
  I was migrating a setup from the older style acl-based host to backend
  mapping, to the newer map-based approach, e.g.
 
  use_backend  %[req.hdr(host),lower,map_beg(mapping.conf,default)]
 
  and that works fine.  But now I'm tempted to simply name the backends
 after
  each servername, (eg. 'mail' from mail.google.com, or 'maps' from
  maps.google.com).
 
  Which in my imagination would look something like:
 
  use_backend %[req.hdr_beg(host),lower]
 
  But is there a way to substring or regex off the front of the host
 string,
  and pass that to the use_backend call?
 
  In other words, continuing the google.com example, if people are hitting
  the server with host: mail.google.com, and maps.google.com, and just
 for
  completeness, notes.books.google.com, I'd like to have backends:
 
  backend mail
 mode http
 foo
 
 
  backend maps
 mode http
 bar
 ...
 
   backend notes.books
 mode http
 baz
 ..
 
  Is there a way to accomplish this without building them into a mapped
 file
  in 1.5.x?
 
  (1.6 solutions are okay too, but won't be able to move to that until it's
  in stable.)

 In 1.6 there's the word converter which stops at the first delimiter,
 so that if you use word(1,.) on notes.books.domain.com, it will return
 notes. From what I understand, in your specific case it does not
 perfectly
 respond to your needs but for many other cases that could be fine. Also it
 makes sense to use it to cut the hostname only and ignore the port.

 Otherwise there's the regsub converter, to which you pass a regex, a
 substitute string, and optionally some flags. There are some limitations
 such as the fact that the comma character cannot be used there due to a
 limitation in the config language which uses it as an argument delimiter,
 but for a domain it's not a problem.

 Thus a fairly complete solution to your need above could look like this :

 use_backend %[req.hdr(host),word(1,:),lower,regsub(\.domain\.com$,)]

 By replacing .domain.com at the end of the name with an empty string,
 it will then return maps, mail, notes.book in your example above.

 Regards,
 Willy

Re: substring matching backend names...

[Willy Tarreau]

Hi,

On Fri, Jul 10, 2015 at 04:32:38PM -0400, Phillip Decker wrote:
 Hello again,
 
 I was migrating a setup from the older style acl-based host to backend
 mapping, to the newer map-based approach, e.g.
 
 use_backend  %[req.hdr(host),lower,map_beg(mapping.conf,default)]
 
 and that works fine.  But now I'm tempted to simply name the backends after
 each servername, (eg. 'mail' from mail.google.com, or 'maps' from
 maps.google.com).
 
 Which in my imagination would look something like:
 
 use_backend %[req.hdr_beg(host),lower]
 
 But is there a way to substring or regex off the front of the host string,
 and pass that to the use_backend call?
 
 In other words, continuing the google.com example, if people are hitting
 the server with host: mail.google.com, and maps.google.com, and just for
 completeness, notes.books.google.com, I'd like to have backends:
 
 backend mail
mode http
foo

 
 backend maps
mode http
bar
...
 
  backend notes.books
mode http
baz
..
 
 Is there a way to accomplish this without building them into a mapped file
 in 1.5.x?
 
 (1.6 solutions are okay too, but won't be able to move to that until it's
 in stable.)

In 1.6 there's the word converter which stops at the first delimiter,
so that if you use word(1,.) on notes.books.domain.com, it will return
notes. From what I understand, in your specific case it does not perfectly
respond to your needs but for many other cases that could be fine. Also it
makes sense to use it to cut the hostname only and ignore the port.

Otherwise there's the regsub converter, to which you pass a regex, a
substitute string, and optionally some flags. There are some limitations
such as the fact that the comma character cannot be used there due to a
limitation in the config language which uses it as an argument delimiter,
but for a domain it's not a problem.

Thus a fairly complete solution to your need above could look like this :

use_backend %[req.hdr(host),word(1,:),lower,regsub(\.domain\.com$,)]

By replacing .domain.com at the end of the name with an empty string,
it will then return maps, mail, notes.book in your example above.

Regards,
Willy

substring matching backend names...

[Phillip Decker]

Hello again,

I was migrating a setup from the older style acl-based host to backend
mapping, to the newer map-based approach, e.g.

use_backend  %[req.hdr(host),lower,map_beg(mapping.conf,default)]

and that works fine.  But now I'm tempted to simply name the backends after
each servername, (eg. 'mail' from mail.google.com, or 'maps' from
maps.google.com).

Which in my imagination would look something like:

use_backend %[req.hdr_beg(host),lower]

But is there a way to substring or regex off the front of the host string,
and pass that to the use_backend call?

In other words, continuing the google.com example, if people are hitting
the server with host: mail.google.com, and maps.google.com, and just for
completeness, notes.books.google.com, I'd like to have backends:

backend mail
   mode http
   foo
   

backend maps
   mode http
   bar
   ...

 backend notes.books
   mode http
   baz
   ..

Is there a way to accomplish this without building them into a mapped file
in 1.5.x?

(1.6 solutions are okay too, but won't be able to move to that until it's
in stable.)

Phillip